Key considerations
- False alarms if sensitivity is high
- Quality varies between batches
- Straps can be cut quickly
- Remote range is short
Pros
- Cheap
- Loud
- Easy to install
- Remote arming
Considerations
- No tracking
- Can be removed quickly
- Plastic housing

Representative photo. Product photos and current options are on the Amazon listing.
This is the archetype of the inexpensive vibration alarm sold widely online: a small box that straps or bolts to the frame, a key-fob remote to arm and disarm, adjustable sensitivity and a loud siren. It costs very little, runs on a rechargeable battery or coin cells depending on the version, and will startle a casual thief. It is also prone to false alarms in wind or when a bike rack neighbor bumps you until you dial the sensitivity down. Treat it as a deterrent layer for low-risk parking — not as security on its own.
Current price and availability are shown on Amazon.
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Pros
Considerations
Goes well with

Best for: High-value e-bikes locked outdoors · Urban and campus parking with theft pressure · Riders who leave the bike in one spot all day
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Best for: Daily commuters in suburban and campus settings · Riders who want the lock mounted to the frame · Mid-value e-bikes
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Best for: iPhone owners · Urban and suburban parking · Pairing with a good lock
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The Knog Scout does two jobs: it is a motion alarm that screams when the bike is moved, and it is an Apple Find My device so you can locate it like an AirTag. It bolts to the bottle-cage bosses with security screws and is controlled from the Knog app. The alarm is loud enough to make a thief reconsider a quick grab, and it arms and disarms automatically as your phone comes and goes. It is iPhone-only for the Find My function. Rechargeable via USB-C. It works best as a layer on top of a real lock, not a substitute.
Best for: iPhone users who want alarm plus location · Bikes parked briefly outside shops · Tamper deterrence
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The Foldylock Compact is a lighter, less expensive folding lock that still earned a Sold Secure rating and comes with a tidy frame case. It is a good match for riders who stop at shops and cafes several times a day and want something they will actually reach for instead of rolling the dice on a cable. The links open wide enough for most e-bike frames plus a wheel and a rack, and the keyed cylinder is better than the bargain folding locks flooding the market. It is not in the same class as the ABUS 6500 for serious theft pressure, so treat it as a mid-risk lock.
Best for: Quick stops and errands · Suburban and campus parking · Riders who want light weight over maximum security
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